Thermostatic switch



Nov. 27, 1934. c, J, WERNER 1,981,933

7 THERMOSTATIC SWITCH Filed Feb. 2, 1951 INVENTOR lmw film, r5 54,

ATTORN EYS Patented Nov. 27, 1934 THERMOSTATIC SWITCH Calvin .1. Werner, Dayton, Ohio, assignor, by

mesne assignments, to ration, Detroit, Mich; ware General Motors Corpoa corporation of Dela- Application February 2, 1931, Serial No. 512,869

10 Claims. This invbntion relates to improvements in electric switches.

It is among the objects of the present invention to provide an electric switch which is adapted to control an electric circuit in accordance with temperature conditions.

A further object of the present invention is to provide an electric switch with a thermostatic control device adapted automatically to open the switch to break the circuit when an excessive current is flowing through said circuit.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawing wherein a preferred embodiment of one form of the present invention is clearly shown.

In the drawing:

Fig. 1 is a plan view of the switch with the go cover removed, various elements of the switc being shown in circuit making position.

Fig. 2 is a view similar to Fig. 1, with the elements of the switch shown in the circuit breaking position due to an over-load in the circuit.

25- Fig. 3 is a detail sectional view taken along the line 3-3 of Fig. 1.

Fig. 4 is a sectional view taken along the line 4-4 of Fig. 1.

Fig. 5 is a sectional view taken along the line 55 of Fig. 1.

Fig. 6 is a fragmentary sectional along the line 6-6 of Fig. l.

Referring to the drawing, the switch is shown comprising a housing made up of any suitable insulating material such as molded phenolic condensation product or bakelite. A stationary contact 21 is secured in the housing 20 by a stud 22 which extends beyond the bottom surface 23. of the housing to form a terminal designated by the numeral 24. The contact 21 as shown in the Fig. 3 has an angular portion 25 which is substantially parallel to a similar angular portion 27 of another stationary contact member 28. This contact 28 is secured to the housing 20 by a stud 29, providing the terminal 30.

It will be seen in Fig. 3 that the portions 25 and 27 of the stationary contact members 21 and 28 respectively are in spaced relation. Thesepor tions 25 and 2'7 are yieldable so that the movable contact 31, when moved between said portions 25 and 2'7, must urge said portions apart to ef- Iect good contact engagement. Movable contact 31 is carried by an arm 32 of insulating material which is secured between adjacent tongues 33 and 65 34 of the yoke arms 35 and 36. The tongues 33 view taken and 34 of said yoke arms are riveted together as shown in Fig. 6, tightly clamping the insulating arm 32 therebetween. The opposite ends of the yoke arms are provided with V-shaped notches 38 which receive the pivoted lugs 39 of the pivot bracket 40. This pivot bracket 40 has two other pivot lugs 41 which are engaged by V-shaped notches 42 provided in the yoke end of the actuator 43. A spring 44 is connected between a pin 45 on the actuator 43 and an extension 46, provided by the insulating arm 32, which extends beyond the clamping tongues 33 and 34 of the movable contact carrier. The movable contact carrier comprising members 32, 33 and 34, forms one arm of a toggle joint, the other arm thereof being formed by the actuator 43. The spring 44 interposed therebetween quickly shifts the movable contact intoand out of engagement with the portions 25 and 27 of the stationary contact members as the actuator 43 is moved from one to its other extreme position. This provides a toggle type, quick make-and-break switch.

A plate is secured in the housing, said plate supporting a pivot post 51 which pivotally supports the trigger 52. Trigger 52 comprises two arms 53 and 54, the former having an ear 56. A spring is provided about the pivot post 51 and urges the trigger in a clockwise direction as regards Figs. 1 and 2, and thus the outer end portion of arm 54 is normally urged into engagement with the pin 45 on the actuator 43, which extends from one side of said actuator. When trigger ear 56 is released by catch 59 on the thermostat 58, which is detailedly described hereinafter, spring 55 will overcome the eliect of the spring 44, which urges the contact 31 into circuit making position, and also will overcome the friction of the mechanism. However, spring 44, tending to pull the actuator 43 counterclockwise as in Fig. 1 when said lever has been operated to cause the spring 44 to throw lever 32 into the contact making position, exerts a pressure upon the lever 54 in a counter-clockwise direction and thus reacts against the effect of spring 55 which urges the lever 54 in a clockwise direction. This greatly reduces the gripping effect of the trigger portion 56 upon the catch 59 of the thermostatic element and thereby provides for smother operation by eliminating the usual jerky movement of the thermostatic element when overcoming undue friction.- From this it may be seen that the trigger normally yieldably urges the actuator into the position as shown in Fig. 2 in which the lighter tensioned spring 44 of the toggle joint will maintain the movable contact out of engagement with its cooperating stationary contact portions 25 and-27. A nut on a screw threaded portion of the post 51 maintains the housing cap '70 upon the housing 20;

A bi-metallic thermostatic element 58 is supported between opposite walls of the housing 20. This thermostatic element has an extension or catch 59 adapted to be engaged by the angular portion 56 of the arm 53 when it is shifted by the actuator 43 as it is moved to shift the movable contact 31 into engagement with its stationary contact portions 25 and 27. This position of the arm 53 of the trigger, in which said trigger is detained in the cocked position, is clearly illustrated in the Fig. 1. The trigger being detained in the cooked position as shown in Fig. 1 by the thermostatic detent or catch 59 does not prevent manual operation of the actuator 43 to the position asshown in Fig. 2 in which the movable contact is shifted to contact disengaging position. From normal position, the first operation of the actuator into contact engaging position moves the trigger into its cocked position as shown in Fig; 1, after which said trigger remains in this position until the thermostat is warped, by increased temperature, to release it. The switch is manually operable during the entire time that the trigger is mantained in cocked position.

A terminal 62 is provided on the housing and between it and the terminal 30 a heater coil 63 is connected so as to lie adjacent the thermostatic element 58. Excessive currents flowing through the heater coil 63 and consequently across the stationary and movable contacts, which are in circuit with the heater coil, will cause a predetermined high temperature to be attained which will effect warping of the thermostatic element 58 and thereby cause the catch 59 thereof to be moved out of engagement with the trigger portion 56 and consequently the trigger is released. Upon the release of the trigger, it being springloaded, the return thereof to normal position will move the actuator from the position as shown in Fig. 1, or more specifically the contact making position, into the position as shown in Fig. 2, or the contact breaking position, thereby breaking the circuit in which the excessive current has been flowing.

After the cause of the excessive current has been removed, the next operation of the actuator 43 into its contact making position will again move the trigger into the cocked position, where it will be retained by the thermostatic element to permit continued operation of the switch until another predetermined high temperature is attained due to some reason or another, at which time the trigger will again be released to return the actuator and its contact to its normal position.

Applicant in his present invention has provided a switch which, when moved to the circuit closing position, sets an intermediate member which is not adapted to affect the operation of the switch in any manner unless an excessive or dangerous current is caused to flow through the circuit, at which time said intermediate member will cause the switch to be operated to circuit breaking posi tion.

Applicant has provided a switch of a sturdy and simple structure and design, capable of being produced at a minimum expense of material and time.

While the form of embodiment of the present invention as herein disclosed, constitutes a preferred form, it is to be understood that other forms might be adopted, all coming within the scope of the claims which follow.

What is claimed is as follows:

1.- An automatic switch comprising, in combi nation, a stationary contact; a movable switch actuator; a thermostatic element having a catch; a pivoted'trigger normally engaging and urging the movable switch actuator into normal circuit breaking position, said trigger, however, being movable by said actuator directly to engage the catch of the thermostatic element and be retained by it, whereby the switch actuator may be operated without being engaged by the trigger, the thermostatic element however being adapted to release the trigger at a predetermined high temperature whereby the trigger will again engage and urge the movable switch actuator into normal circuit breaking position.

2. An automatic switch comprising, in combination, a stationary contact; a movable contact adapted to engage the stationary contact; a manually operable toggle joint provided with a spring for shifting said movable contact substantially quickly in opposite directions; a pivoted, spring loaded trigger engaging a member of the toggle joint and normally urging it into the contact disengaging position, said trigger being movable by said toggle joint as it is moved into contact engaging position; and a thermostatic element having a catch adapted directly to engage and detain the trigger when it is moved by the toggle joint, said thermostatic element releasing the trigger to cause it to shift the toggle joint into contact disengaging position in response to a predetermined high temperature.

3. A switch comprising, in combination, a stationary contact; a movable contact adapted to be shifted into engagement with the stationary contact; an actuator and a lever forming a toggle for actuating the movable contact; a thermostatic element providing a catch; a trigger having a portion engageable by the actuator of the toggle to move the trigger out of normal position directly into engagement with the catch on the thermostatic element as the actuator of the toggle is operated .to move the movable contact into engagement with the stationary contact; a spring connectedbetween the actuator and the lever of the toggle; and a spring urging the trigger into normal position, said spring having suflicient tension to overcome the reactionary force of the toggle spring acting through the actuator and the friction of the mechanism.

4. A switch comprising, in combination, cooperating stationary and movable contacts; an actuator for the movable contact comprising a toggle having two pivoted levers with a tension spring interposed; a thermostatic element provided with a catch; a trigger adapted to be shifted into direct engagement with the catch by the movement of the actuator to contact closing position; and a spring on the trigger, urging it into normal position in which it yieldably maintains the actuator in contact opening position, said spring having a tension sufiicient to overcome the tension of the actuator spring which hold the contacts in contact making position and the friction of the switch mechanism.

5. An automatic switch comprising, in combination, a stationary contact; a movable contact adapted to be shifted into engagement with the stationary contact; means including a manually operable actuator for actuating the movable contact; a thermostatic member providing a catch; a trigger member pivotally mounted on a fixed pivot and having arms extending angularly at an acute angle from the pivotal mounting therefor, one of said arms operatively engaging the actuator and the other of said arms being adapted to engage said catch; resilient means urging the trigger about its pivotal mounting in one direction, engagement of said arm and catch normally preventing movement of the trigger due to the urging of the resilient means; and means including said thermostatic member for releasing said arm from said catch in response to a temperature change, the other arm moving the actuator.

6. An automatic switch comprising, in combination, a stationary contact; a movable contact adapted to be shifted into engagement with the stationary contact; means including an actuator for actuating the movable contact; a thermostatic member providing a catch; a trigger member pivotally mounted on a fixed pivot and having rigidly connected arms extending angularly from the pivotal mounting therefor, one of said arms operatively engaging the actuator, and the other of said arms being adapted to engage said catch; a spring mounted upon said fixed pivot and urging the trigger about its pivotal mounting in one direction; means including said thermostatic member and catch for controlling movement of the trigger to efiect control of the actuator movement caused by said spring and the engagement of said arm and actuator.

7. In an automatic switch, the combination comprising, a thermostatic member providing a catch; a pivotally mounted switch actuator; a pivotally mounted trigger biased in one direction and having angularly extending arms, one of said arms extending substantially transversely to the actuator and adapted to engage said catch, the other of said arms directly engaging the actuator to move the actuator in one direction.

8. In an automatic switch, the combination comprising, a thermostatic member providing a catch; a movable switch actuator; a pivotally mounted trigger biased in one direction and having angularly extending arms, one of said arms extending substantially transversely to the actuator and adapted to engage said catch, the other of said arms directly engaging the actuator'so that said trigger is moved by the actuator against the biasing force and into engagement with the catch. v

9. In an automatic switch, the combination comprising, a thermostatic member providing a catch; a movable switch actuator; a pivotally mounted trigger biased in one direction and having extending arms, one of said arms adapted to directly engage said catch, and the other of said arms directly engaging the actuator.

10. In an automatic switch, the combination comprising, a thermostatic member providing a catch; a movable switch actuator; a trigger pivotally mounted on a fixed pivot and having ex- CALVIN J. WERNER. 

